Active-Layer Thickness estimation in the Yukon–Kuskokwim Delta, Alaska, via inversion of InSAR data and field measurements
Refereed conference paper presented and published in conference proceedings


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AbstractThe active layer in permafrost environments plays a critical role in land surface processes, surface hydrology, vegetation succession, and thermokarst processes. We define the active layer as the uppermost portion of the ground subject to annual freeze/thaw cycles. Measuring the active layer thickness provides valuable insight into the above-mentioned processes, but due to the heterogenous nature of active layer thickness and the sparsity of traditional measurement methods, accurately characterizing the active layer thickness across broad permafrost regions can be very challenging. We apply interferometric synthetic aperture radar (InSAR) to measure the active layer thickness to study permafrost processes in the Yukon-Kuskokwim (YK) delta in southwest Alaska. This area is a lowland marsh characterized by low-gradient meandering rivers and numerous lakes, several of which are thermokarst thaw lakes. Using ALOS PALSAR data acquired between 2007-2011, we generate a time-series of cm-scale surface deformation, from which we determine both seasonal subsidence and long-term (secular) thermokarst subsidence. We use a previously-developed algorithm to infer active-layer thickness across the study region from the InSAR-derived surface deformation maps. In addition, we compare in-situ field measurements of active layer thickness, organic layer thickness, and soil saturation acquired by ground-penetrating radar and mechanical probing measurements during a field campaign to the YK delta in August 2016. Finally, we discuss the uncertainty in our inversion results, and several coherence-based and phase variance-based data masking techniques for optimal active-layer thickness reconstruction.
All Author(s) ListMichaelides Roger, Zebker Howard, Schaefer Kevin, Chen Jingyi, Parsekian Andy, Jafarov Elchin, Liu Lin
Name of ConferenceAmerican Geophysical Union, Fall Meeting 2016
Start Date of Conference12/12/2016
End Date of Conference16/12/2016
Place of ConferenceSan Francisco
Country/Region of ConferenceUnited States of America
Book titleAGU Fall Meeting
Year2016
Month12
PublisherAGU
LanguagesEnglish-United States

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